Bottom-Up or Top-Down Approach? Understanding the Way to Reach the Milestone of Recovery in Stroke

Abstract

Editorial Stroke is the third most frequent cause of death worldwide and the leading cause of permanent disability in the USA and Europe. Stroke survivors can suffer several neurological deficits or impairments, such as hemiparesis, communication disorders, cognitive deficits or disorders in visuo-spatial perception. These impairments have an important impact in patient's life and considerable costs for health and social services. Moreover, after completing standard rehabilitation, approximately 50%-60% of stroke patients still experience some degree of motor impairment, and approximately 50% are at least partly dependent in activities-of-daily-living. Evidences about post-stroke motor recovery in human and nonhuman animal models suggest that there is a 'sensitive period' post-stroke: first, almost all recovery from impairment occurs in the first 3 months after stroke in humans and in the first month after stroke in rodent models. Secondly, the effectiveness of post-stroke training with respect to impairment diminishes as a function of time after stroke in primates and in rodents. Therefore, there is a general concordance between animal and human studies that rehabilitation in the sensitive period is essential for significant recovery from impairment. Up to now, a wide range of strategies and devices have been developed for the purpose of promoting motor recovery after stroke by taking advantage from the brain's ability to reorganize its neural networks after the injury. Traditional approaches towards rehabilitation can be qualified as "bottom-up" approaches in the sense that they act on the physical level and expect for changes at the central neural system level. Currently, robotic technologies and mechatronic devices represent the modern version of bottom-up treatment, offering the recognised advantage of providing quantifiable and repeatable task-specific assistance that ensure consistency during the rehabilitation and being cost-efficient.